The present invention relates to a transmission operating device and, more particulary, to a transmission operating device using control cables as a means for transmitting an operational force.
A control cable comprises fundamentally a flexible conduit and a flexible inner wire comprising a strand of steel wire, which is slidably inserted into the conduit, and is constructed so as to transmit a push or pull load acted on one end of the inner wire to the other end in order to operate a remote driven device.
A transmission operating device using control cables is recently used as a means for remotely operating a gear transmission in a vehicle such as a front-wheel-drive light motorcar having a front engine and a rear-wheel-drive bus or truck having a rear engine. According to such a transmission operating device, weight and cost thereof are reduced and assembling work is made easy.
In general, such a transmission operating device has two control cables which are arranged parallel to each other. When operating a change speed lever of the device in one direction, the operational force is transmitted to the transmission via one control cable so that a selecting operation can be performed. When operating the change speed lever in the other direction, the operational force is transmitted to the transmission via the other control cable so that a shifting operation can be performed.
Such a transmission operating device is described in British Pat. No. 979,574. As shown in FIG. 9, the transmission operating device uses a ball joint 52 for supporting a change speed lever 51 to the frame (not shown in the drawing). When the change speed lever 51 is operated in the shifting direction, the operational force is directly transmitted to a shifting rod 53 via a lower end of the change speed lever 51. On the other hand, when the change speed lever 51 is operated in the selecting direction, the operational force is transmitted to a selecting rod 56 via a bell crank 55 having a long slit for allowing the change speed lever 51 to move in the shifting direction without moving the bell crank 55. Further, the transmission operating device is provided with a mechanism 57 for preventing the change speed lever 51 from rotating around an axis of the lever 51.
On the other hand, a device described in Japanese unexamined patent publication No. 149135/1979 is also known. As shown in FIG. 10, a change speed lever 61 is provided to the frame (not shown in the drawing) via a carrier 62. The carrier 62 supports the change speed lever 61 so that the change speed lever 61 can be operated in the shifting direction (in the direction of Arrow C or Arrow D), and the carrier 62 per se is supported on the frame so as to rotate in the selecting direction (in the direction of Arrow A or Arrow B). Further, a lower end of the change speed lever 61 is connected with a shifting rod. A projecting member 64 provided in a neighbourhood of the lower end of the carrier 62 is connected with an end of a bell crank 65 via a ball joint 66. The other end of the bell crank 65 is connected with the shifting rod 67.
In the above described devices, a design for arranging each part is disadvantageously complicated, since the mechanism for transmitting an operational force from the change speed lever to the control cable is gathered to a lower portion of the device. Further, an assembling work and a maintenance work are disadvatageously difficult. Further, the device having a ball joint 52 in FIG. 9 requires the mechanism 57 for preventing the change speed lever from rotating around the axis of itself and, therefore, the structure of the device tends to be more complicated.
When constructing a transmission operating device using control cables, in general, it is most important to design a mechanism transmitting a force from the change speed lever to a control cable for selecting. In that case, since it is necessary to construct so that the selecting side cannot be subject to the influence of the shifting operation during the shifting operation, such a transmission operating device satisfying the requirement tends to become complicated and the operation of such device is not smooth.
An object of the present invention is to resolve the above described problems concerning the conventional device, and to provide a transmission operating device in which the mechanism is simplified, and which can be smoothly operated.